India's population has a direct impact on the country's vulnerability to climate change. Here are the factors responsible for India's vulnerability to climate change and the role of heavy population:

• Resource overuse: The increasing population in India is putting a strain on natural resources like water, land, and forests. This overuse of resources is leading to environmental degradation and making the country more vulnerable to climate change.
• Urbanization: The rapid urbanization in India has led to congestion, air pollution, and waste generation. This is leading to climate change as the world's cities are responsible for 70% of global greenhouse gas emissions.
• Low literacy rate and political instability are major factors responsible for the lack of awareness about the importance of a sustainable environment in India. Poverty, lack of resources, and corruption make it difficult for the country to adapt to climate change.
• Heavy population also leads to more greenhouse gas emissions, making India one of the top emitters of carbon dioxide in the world. The increasing population is putting more pressure on the country to meet the energy demands, which is leading to climate change.

Overall, India's heavy population is part of the reason why the country is vulnerable to climate change, as it puts a strain on natural resources, leads to urbanization, and increases greenhouse gas emissions. A combination of government policies, awareness campaigns, and the use of sustainable technologies may help in mitigating the effects of climate change in India.